Business minister Margot James wrote to HM Revenue and Customs over claims by some delivery staff that they are entitled to the minimum amount but do not receive it, the Department for Business, Energy and Industrial Strategy confirmed.

In July there were claims that some couriers feel they are "treated like dirt" and have faced losing work for attending hospital appointments or tending to sick relatives.

The details of complaints made about Hermes by current and former staff were revealed in a letter sent to PM Theresa May by the chairman of the Commons Work and Pensions Select Committee, Frank Field, urging her to launch an investigation.

Mr Field's office said that in response the PM has acted by asking Ms James to invite HMRC to begin inquiries.

He published a report on Monday, based on 78 testimonies, which details some of the working practices at Hermes, and contains a series of recommendations for a decent minimum standard to be applied at Hermes and across the courier industry.

Allegations in the report include two parents being threatened with a loss of work while sat at their dying son's bedside, and an immediate loss of work for somebody who attended an urgent hospital appointment.

Hermes said it was confident its agreements with couriers represented "legitimate self-employment" but would co-operate with any investigation.

The company said it is unable to comment on the allegations in Mr Field's report without knowing more detail.

Mr Field said: "This is the first practical move the Prime Minister has made to begin implementing the promise she made on entering Downing Street - that there will be no-one left behind in this country.

"Woe betide those employers who think they can beat Government moves to guarantee a decent minimum for everyone."